Transcribing music from from WAVE file (.wav, .wave) to a MIDI (.mid, .midi) file is very possible and actually frequently make audio conversion. What such wav to midi conversion does, is to convert the audio data and creates a file with musical instrumental data that can be replayed with any MIDI player.
Open WAV file Open MIDI fileA music composition and editing program
A music notation and transcription software
Tool for load your own WAV files into your Nord keyboard